2D evaluation

Bender, A., Mussa, H.Y., Glen, R.C., and Reding, S. (2004) Similarity searching of chemical databases using atom environment descriptors (MOLPRINT 2D) evaluation of performance. Journal of Chemical Information and Computer Sciences, 44 (5), 1708-1718. 

Johnson et al 2007). In both studies a similar accuracy was reported for the detection of polyps, though the review time was significantly reduced both studies reported approximatelyl4 minutes for primary 2D evaluation and about 10 minutes for 3D virtual dissection. 

Several clinical studies have used primary 2D evaluation in high prevalence populations. Primary 3D evaluation, however, has only been performed in comparative studies of 2D and 3D, not in clinical studies. 

VAN Gelder et al. (2004c) compared primary 2D evaluation with a primary 3D evaluation method (unfolded cube projection) in a series of 77 patients. Mean sensitivity for large polyps for the primary 3D and 2D review methods were 83 and 72%, respectively. The specificity was 92 and 94% respectively. Fewer perceptive errors, although not statistically significant (p=0.06), were made with the primary 3D method than with the primary 2D method although at expense of a slight increase of the number of false positives. 

The second cause of its time consuming nature is the extra time needed to examine a colon compared to the 2D method. The cause of this problem lies within the fact that to cover as much colonic surface as possible with conventional 3D methods, evaluation in both antegrade and retrograde direction is mandatory. Consequently, in comparative studies primary conventional 3D evaluation requires an extra 50 to 70% in interpretation time compared to 2D evaluation (McFarland et al. 2001 Iannaccone et al. 2004b). 

Studies that used display modes that did not require bidirectional fly-through demanded less extra time or were even faster compared to 2D evaluation. Van Gelder et al. who used an unfolded cube display only used an additional 15% evaluation time... 

The blue-emitting component of most television screens and computer terminals is another sulfide, ZnS Ag,Al. Although rare-earth activated blue-emitting phosphors ZnS Tm " and Sr (P0 2d-Eu (30) have also been evaluated for this appHcation, the search for a good blue phosphor that does not saturate at high current densities and maintains weU continues. 

Hensley ei al.,n reported the only direct experimental observation of head-to-head linkages in PS by 2D INADEQUATE NMR on, 3C-enriched PS. The method did not enable these groups to be quantified with sufficient precision for evaluation of W tc- Zammit el a/.130 studied chain distribution of low molecular weight PS prepared with AIBN initiator by MALDI-TOF. Separate distributions of chains formed by combination and disproportionation were observed. They estimated kJkK. at 90 °C to be 0.057. 

The large amount of data on k2h/ 2D and ft for these azo coupling reactions allowed a critical comparative evaluation of these indices in relation to the problem of the symmetry of transition states in proton transfer reactions (Hanna et al.,... 

The [Fe4S4p clusters contain four equivalent irons and give relatively narrow signals (3, 7, 62, 63) (Fig. 2E). The electron relaxation time is evaluated around 5 X 10 s (Table I), which is somewhat smaller than that of the Fe(II) monomer. Also, the signals of [Fe4S4l (15, 64-68) (Fig. 2D) and [Fe4S4fi+ (8, 13, 69-71) (Fig. 2F) systems are sharp. 

For detection of compounds in complex mixtures 2D methods are often needed. However, application of 2D correlation NMR experiments and advanced field gradient techniques is still fairly limited and awaits the possibility of quantitative evaluation. 

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